MCMedicalCodingSoftware
M21.06

M21.06: Valgus deformity, not elsewhere classified, knee

Non-billable headerICD-10-CM

M21.06 is a non-billable header ICD-10-CM code for valgus deformity, not elsewhere classified, knee. It cannot be billed on its own: choose one of the more specific child codes below.

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Genu valgum
  • Knock knee

Excludes1 inherited from the categories above M21.06

A category’s note binds every code beneath it.

Written on M21.0: Valgus deformity, not elsewhere classified

  • metatarsus valgus (Q66.6)
  • talipes calcaneovalgus (Q66.4-)

Written on M21: Other acquired deformities of limbs

  • acquired absence of limb (Z89.-)
  • congenital absence of limbs (Q71-Q73)
  • congenital deformities and malformations of limbs (Q65-Q66, Q68-Q74)

Excludes2 inherited from the categories above M21.06

Not part of this code, but both may be coded when both are present.

Written on M21: Other acquired deformities of limbs

  • acquired deformities of fingers or toes (M20.-)
  • coxa plana (M91.2)

Other codes that can never be billed with M21.06

Their own Excludes1 notes name this code, so the conflict is not listed above.

  • M23Internal derangement of knee

Risk adjustment

No CMS-HCC V28 category: this code does not change a RAF score.

Code history

Unchanged in every release from FY2024 to FY2027.

Code to one of these instead M21.06

3 child codes. Green means billable.

Other codes under M21.0

ICD-10-CMFY2027· effective October 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release: see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.